The lifetime risk of heart failure is approximately 20%, and heart failure is the leading cause of hospitalization in the elderly. The presence of chronic renal insufficiency (CRI) is associated with a doubling in risk for incident heart failure, compared with normal renal function, and with a nearly two-fold mortality risk in persons with established heart failure. Moreover, the diagnosis of heart failure is difficult in the setting of CRI because of the considerable overlap in the symptoms of the two conditions, and the treatment of heart failure is complicated by CRI due to increased risk from medical and surgical therapies. Currently, little is known about the determinants of heart failure in persons with CRI, the relative incidence of systolic and diastolic heart failure, and the prognostic factors for survival in persons with coexisting CRI and heart failure. The Chronic Renal Insufficiency Cohort (CRIC) is a multi-center, longitudinal study funded by the National Institute for Diabetes, Digestive and Kidney diseases to investigate the mechanisms for kidney disease progression and cardiovascular disease events in 3,000 persons with CRI. The CRIC Heart Failure Ancillary study, proposed herein, will comprehensively investigate the development and progression of heart failure in this high-risk population. The goals of the study will be to provide novel, scientific discoveries that lead to the identification of persons at increased heart failure risk, the early detection of incident heart failure, and the prolongation of heart failure survival. The CRIC Heart Failure Ancillary study will add Color M-mode Doppler echocardiography to CRIC to study the prevalence of asymptomatic diastolic dysfunction and its importance to heart failure development and outcomes. Serum markers that signal increased left ventricular pressure (N-terminal pro-B-type natriuretic peptide (proBNP)), inflammation (highly sensitive C-reactive peptide (hsCRP)), and myocardial cell injury (troponin-T) will be evaluated as potential risk factors for the onset of heart failure, as diagnostic tests to identify clinical heart failure, and as prognostic factors in participants with established heart failure. An additional important outcome of the CRIC Heart Failure Ancillary will be health-related quality of life in participants with CRI and heart failure, which will be evaluated annually using both general and disease specific instruments. This Ancillary study will provide novel insights into the unique set of risk factors that lead to heart failure in persons with CRI, and potential mechanisms to delay and prevent its onset. Because the symptoms of CRI and heart failure can be similar, proBNP may be an invaluable test for detecting heart failure and for monitoring its progression. In persons with established heart failure and CRI, the combination of proBNP, hsCRP, and troponin-T may be optimal for risk stratification and informing long-term prognosis.